Migraine headaches occur in approximately 12% of the world population. Therefore, in the United States in the year 2005 there are approximately 30 million people who suffer from this affliction. Although medicines have been created that significantly diminish the suffering of migraine patients, these medicines are often contraindicated and have highly undesirable side effects and many patients do not obtain satisfactory relief from the severe headache pain, nausea and other discomforts associated with migraine. Furthermore, migraine headaches are typically treated after they have become painful, i.e., the treatment is often ineffective in preventing the onset of the migraine headache. Other than some drugs that are efficacious for some patients, there is currently no known treatment for migraine headaches that can be applied after a patient detects an aura of that headache to prevent the occurrence of pain and other undesirable manifestations of that migraine headache. A non-invasive, non-drug method for preventing the occurrence of migraine headaches would be a remarkable boon for those millions of people all over the world who suffer from these painful and often debilitating experiences.
In 1985, A. T. Barker, et al (Lancet, 1985, pp. 1105-1107) described the use of a coil placed over the scalp which produced a high intensity, time varying, magnetic field. This magnetic field produces an electric current in the cortex of the human brain which can in turn produce certain effects on brain neurons. This type of system has been given the name Transcranial Magnetic Stimulation (TMS). If continuously repetitive magnetic pulses are applied in this manner, it has been given the name rTMS.
In an article from Advances in Therapy, May/June 2001 and entitled “Impulse Magnetic-Field Therapy for Migraine and Other Headaches: A Double-Blind, Placebo-Controlled Study,” by R. B. Pelka, et al, there is described a device using an alternating magnetic field source placed on a ribbon around the patient's neck. All devices were no more than 12 inches from the patient's head. The intensity of the 16 Hz magnetic field at the source was 5 microTesla. For all patients, the field at the brain had to be less than 1.0 microTesla. This field was applied for 4 weeks with some benefit being reported in 1 to 3 weeks. The wearing of such a device for weeks is certainly inconvenient as compared to a single magnetic pulse applied for a fraction of a millisecond or at most, a few such pulses. It is also believed that a magnetic field strength of only 1 microTesla would be totally insufficient to erase the aura that precedes many migraine headaches.
In the journal Neurology (Apr. 11, 2000, pp. 1529-1531) it has been reported by B. Boroojerdi, et al that rTMS at a rate of one pulse per second can create a reduction of the excitability of the neurons of the human visual cortex. However, that article did not indicate that TMS or rTMS can be used for the preventing the occurrence of migraine headaches or diminishing the intensity or duration of a migraine headache.
In U.S. Pat. No. 6,402,678, Robert E. Fischell et al describe means and methods for the treatment of migraine headaches using a portable device that is placed onto the patient's head. This device is used to create a magnetic pulse that acts upon the neurons of the brain and can eliminate both the aura that occurs prior to a migraine headache and a migraine headache after it has started. However, since the entire device is placed onto the patient's head, it is somewhat awkward for the patient's use. Furthermore, since the triggering controls are also located on the head mounted device, their operation is also somewhat difficult.
In U.S. patent application Ser. No. 10/929,586, Robert E. Fischell et al describe an improved device for applying TMS to the neurons of the brain. However, that application does not describe any means to limit the number of TMS pulses that a patient can place onto his or her head, nor does that application describe any means for verifying that the TMS device is operating properly. Still further, that prior application did not conceive of the main features of the present invention which is a one-piece, hand-held portable unit that contains all the circuitry and a magnetic coil for applying a TMS pulse onto the patient's brain.